Expandable interbody spacer

ABSTRACT

Devices and methods for treating one or more damaged, diseased, or traumatized portions of the spine, including intervertebral discs, to reduce or eliminate associated back pain. In one or more embodiments, the present invention relates to an expandable interbody spacer. The expandable interbody spacer may comprise a first jointed arm comprising a plurality of links pivotally coupled end to end. The expandable interbody spacer further may comprise a second jointed arm comprising a plurality of links pivotally coupled end to end. The first jointed arm and the second jointed arm may be interconnected at a proximal end of the expandable interbody spacer. The first jointed arm and the second jointed arm may be interconnected at a distal end of the expandable interbody spacer.

CROSS REFERENCE TO RELATED APPLICATIONS

This Patent Application is a continuation of U.S. patent applicationSer. No. 16/660,174 filed on Oct. 22, 2019 which is a continuation ofU.S. patent application Ser. No. 15/264,677, filed Sep. 14, 2016, whichis a continuation of U.S. patent application Ser. No. 13/941,095, filedJul. 12, 2013, which is a continuation-in-part application of U.S.patent application Ser. No. 13/483,852, filed May 30, 2012, now U.S.Pat. No. 9,044,342, which are incorporated by reference herein in theirentireties for all purposes.

FIELD OF THE INVENTION

The present invention relates to devices and methods for treating one ormore damaged, diseased, or traumatized portions of the spine, includingintervertebral discs, to reduce or eliminate associated back pain. Inone or more embodiments, the present invention relates to an expandableinterbody spacer.

BACKGROUND OF THE INVENTION

The vertebrate spine is the axis of the skeleton providing structuralsupport for the other body parts. In humans, the normal spine has sevencervical, twelve thoracic and five lumbar segments. The lumbar spinesits upon the sacrum, which then attaches to the pelvis, and in turn issupported by the hip and leg bones. The bony vertebral bodies of thespine are separated by intervertebral discs, which act as joints butallow known degrees of flexion, extension, lateral bending, and axialrotation.

The typical vertebra has a thick anterior bone mass called the vertebralbody, with a neural (vertebral) arch that arises from the posteriorsurface of the vertebral body. The centers of adjacent vertebrae aresupported by intervertebral discs. Each neural arch combines with theposterior surface of the vertebral body and encloses a vertebralforamen. The vertebral foramina of adjacent vertebrae are aligned toform a vertebral canal, through which the spinal sac, cord and nerverootlets pass. The portion of the neural arch which extends posteriorlyand acts to protect the spinal cord's posterior side is known as thelamina. Projecting from the posterior region of the neural arch is thespinous process.

The intervertebral disc primarily serves as a mechanical cushionpermitting controlled motion between vertebral segments of the axialskeleton. The normal disc is a unique, mixed structure, comprised ofthree component tissues: the nucleus pulpous (“nucleus”), the annulusfibrosus (“annulus”) and two vertebral end plates. The two vertebral endplates are composed of thin cartilage overlying a thin layer of hard,cortical bone which attaches to the spongy, richly vascular, cancellousbone of the vertebral body. The end plates thus act to attach adjacentvertebrae to the disc.

The spinal disc and/or vertebral bodies may be displaced or damaged dueto trauma, disease, degenerative defects, or wear over an extendedperiod of time. One result of this displacement or damage to a spinaldisc or vertebral body may be chronic back pain. A common procedure fortreating damage or disease of the spinal disc or vertebral body mayinvolve partial or complete removal of an intervertebral disc. Animplant, which may be referred to as an interbody spacer, can beinserted into the cavity created where the intervertebral disc wasremoved to help maintain height of the spine and/or restore stability tothe spine. An example of an interbody spacer that has been commonly usedis a cage, which typically is packed with bone and/orbone-growth-inducing materials. However, there are drawbacks associatedwith conventional interbody spacers, such as cages and other designs.For instances, conventional interbody spacers may be too large and bulkyfor introduction into the disc space in a minimally invasive manner,such as may be utilized in a posterior approach. Further, theseconventional interbody spacers may have inadequate surface area contactwith the adjacent endplates if sized for introduction into the discspace in a minimally invasive manner. In addition, conventionalinterbody spacers designed for introduction into the disc space in aminimally invasive manner may lack sufficient space for packing ofbone-growth-inducing material, thus potentially not promoting thedesired graft between the adjacent endplates.

Therefore, a need exists for an interbody spacer that can be introducedin a minimally manner that provides a desired amount of surface areacontact with the adjacent endplates and has an increased space forpacking of bone-growth-inducing material.

SUMMARY OF THE INVENTION

The present invention relates to an expandable interbody spacer. Theexpandable interbody spacer may comprise a first jointed arm comprisinga plurality of links pivotally coupled end to end. The expandableinterbody spacer further may comprise a second jointed arm comprising aplurality of links pivotally coupled end to end. The first jointed armand the second jointed arm may be interconnected at a proximal end ofthe expandable interbody spacer. The first jointed arm and the secondjointed arm may be interconnected at a distal end of the expandableinterbody spacer. The first jointed arm and the second jointed arm mayeach be configured to fold inward in opposite directions to place theexpandable interbody spacer in an expanded position.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be more readily understood with reference tothe embodiments thereof illustrated in the attached drawing figures, inwhich:

FIG. 1 is a top view of an expandable interbody spacer shown in acollapsed position in accordance with embodiments of the presentinvention;

FIG. 2 is a side view of the expandable interbody spacer of FIG. 1 shownin a collapsed position;

FIG. 3 is a proximal end view of the expandable interbody spacer of FIG.1 shown in a collapsed position;

FIG. 4 is a distal end view of the expandable interbody spacer of FIG. 1shown in a collapsed position;

FIG. 5 is an exploded view of the expandable interbody spacer of FIG. 1;

FIG. 6 is a top view of the expandable interbody spacer of FIG. 1 shownin an expanded position;

FIG. 7 is a right side view of the expandable interbody spacer of FIG. 1shown in an expanded position;

FIG. 8 is a left side view of the expandable interbody spacer of FIG. 1shown in an expanded position;

FIG. 9 is a proximal end view of the expandable interbody spacer of FIG.1 shown in an expanded position;

FIG. 10 is a distal end view of the expandable interbody spacer of FIG.1 shown in an expanded position;

FIG. 11 is a view showing disc space between adjacent vertebrae inaccordance with embodiments of the present invention;

FIG. 12 is a view of a tool for insertion of an expandable interbodyspacer in accordance with embodiments of the present invention;

FIG. 13 is a view showing the tool of FIG. 12 introducing an expandableinterbody spacer into a disc space in a collapsed position in accordancewith embodiments of the present invention;

FIG. 14 is a view showing the tool of FIG. 12 expanding an expandableinterbody spacer in a disc space in accordance with embodiments of thepresent invention;

FIG. 15 is a view showing a funnel for introduction ofbone-growth-inducing material into a disc space in accordance withembodiments of the present invention;

FIG. 16 is an exploded view of another embodiment of an expandableinterbody spacer;

FIG. 17 is a top view of another embodiment of an expandable interbodyspacer shown in a collapsed position;

FIG. 18 is a top view of the expandable interbody spacer of FIG. 17shown in an expanded position;

FIG. 19 is an exploded view of the expandable interbody spacer of FIG.17 ;

FIG. 20 is an exploded view of a link of a jointed arm of the expandableinterbody spacer of FIG. 17 ;

FIG. 21 is a top view of another embodiment of an expandable interbodyspacer shown in a collapsed position;

FIG. 22 is a top view of the expandable interbody spacer of FIG. 21shown in an expanded position;

FIG. 23 is a view of the expandable interbody spacer of FIG. 21 shown ina disc space in a collapsed position;

FIG. 24 is a view of the expandable interbody spacer of FIG. 21 shown ina disc space in an expanded position;

FIG. 25 is a top view of a tool shown engaging the expandable interbodyspacer of FIG. 21 in accordance with embodiments of the presentinvention;

FIG. 26 is a view showing the tool of FIG. 24 expanding the expandableinterbody spacer of FIG. 24 in a disc space in accordance withembodiments of the present invention;

FIGS. 27A-27C show different views of an expandable interbody spacerhaving an expandable containment bladder in accordance with embodimentsof the present invention;

FIGS. 28A and 28B show top views of an expandable spacer utilizing ashim member in accordance with embodiments of the present invention;

FIGS. 29A and 29B show top perspective views of an expandable spacerutilizing a translation member in accordance with embodiments of thepresent invention;

FIGS. 30A and 30B show top views of an expandable spacer including asliding actuation member in accordance with embodiments of the presentinvention;

FIGS. 31A and 31B show different views of an expandable spacer havingslidable wings in accordance with embodiments of the present invention;

FIGS. 32A-32D show an expandable spacer comprising an “I-beam” withmultiple side slots for receiving complementary side members inaccordance with embodiments of the present invention;

FIGS. 33A and 33B show different views of a hinged expandable interbodyspacer in accordance with embodiments of the present invention;

FIGS. 34A-34D show different views of an alternate hinged expandableinterbody spacer in accordance with embodiments of the presentinvention;

FIGS. 35A and 35B show an expandable spacer including a flexiblecontainment member in accordance with some embodiments;

FIG. 36 shows an expandable spacer including a rotating cam to actuateexpandable wings in accordance with some embodiments;

FIGS. 37A and 37B show an expandable spacer including four wingsactuated by a gear mechanism in accordance with some embodiments;

FIGS. 38A and 38B show an expandable spacer including deployable pins inaccordance with some embodiments;

FIG. 39 shows an expandable spacer expandable via a guide wire inaccordance with some embodiments;

FIG. 40 shows an expandable spacer including an add-on member inaccordance with some embodiments;

FIG. 41 shows a buildable spacer that can be guided by tracks in a discspace to form a large footprint in a disc space in accordance with someembodiments;

FIGS. 42A-D show a rotatable spacer capable of expansion followingrotation in accordance with some embodiments;

FIGS. 43A-C show an expandable spacer capable of outward folding inaccordance with some embodiments;

FIGS. 44A and 44B show a pair of expandable spacers having deployablearms;

FIGS. 45A-45C show an expandable spacer having a rack and pinionactuator in accordance with some embodiments;

FIGS. 46A-46C show an expandable spacer having an outer member with aslidable inner member therein;

FIGS. 47A and 47B show an expandable spacer having upper and lowermembers separated by linking members in accordance with someembodiments;

FIGS. 48A and 48B show an expandable spacer comprising a worm gear inaccordance with some embodiments;

FIGS. 49A and 49B show an expandable spacer having asymmetricalexpansion in accordance with some embodiments.

Throughout the drawing figures, it should be understood that likenumerals refer to like features and structures.

DETAILED DESCRIPTION OF THE INVENTION

The preferred embodiments of the invention will now be described withreference to the attached drawing figures. The following detaileddescription of the invention is not intended to be illustrative of allembodiments. In describing preferred embodiments of the presentinvention, specific terminology is employed for the sake of clarity.However, the invention is not intended to be limited to the specificterminology so selected. It is to be understood that each specificelement includes all technical equivalents that operate in a similarmanner to accomplish a similar purpose.

Referring to FIGS. 1-10 , an expandable interbody spacer 10 is shown inaccordance with embodiments of the present invention. In the illustratedembodiment, the expandable interbody spacer 10 has a proximal end 20 anda distal end 30. The expandable interbody spacer 10 may include a firstjointed arm 40 and a second jointed arm 50 positioned on either side oflongitudinal axis 15 of the spacer 10. The first and second jointed arms40, 50 may be interconnected at the proximal end 20, for example, by aproximal connection member 60. The first and second jointed arms 40, 50may be interconnected at the distal end 30, for example, by a distalconnection member 70. The first and second jointed arms 40, 50 Theexpandable interbody spacer 10 may be made from a number of materials,including titanium, stainless steel, titanium alloys, non-titaniumalloys, polymeric materials, plastic composites, polyether ether ketone(“PEEK”) plastic material, ceramic, elastic materials, and combinationsthereof. While the expandable interbody spacer 10 may be used with aposterior, anterior, lateral, or combined approach to the surgical site,the spacer 10 may be particularly suited with a posterior approach.

The first jointed arm 40 has a proximal end 80 and a distal end 90. Theproximal end 80 may be pivotally coupled to the proximal connectionmember 60. The distal end 90 may be pivotally coupled to the distalconnection member 70. Any of a variety of different fasteners may beused to pivotally couple the proximal end 80 and the distal end 90 andthe proximal connection member 60 and the distal connection member 70,such as pins 100, for example. In another embodiment (not illustrated),the connection may be a hinged connection. As illustrated, the firstjointed arm 40 may comprise a plurality of links that are pivotallycoupled to one another. In the illustrated embodiment, the first jointedarm 40 comprises first link 110, second link 120, and third link 130.When the spacer 10 is in a collapsed position, the first link 110,second link 120, and third link may be generally axially aligned. Asillustrated, the first link 110, second link 120, and third link 130 maybe connected end to end. When the spacer 10 is in a collapsed position,the first link 110, second link 120, and third link 130 may be generallyaxially aligned. The first link 110 and the second link 120 may bepivotally coupled, and the second link 120 and the third link 130 mayalso be rotatably coupled. Any of a variety of different fasteners maybe used to pivotally couple the links 110, 120, 130, such as pins 100,for example. In another embodiment (not illustrated), the coupling maybe via a hinged connection.

As best seen in FIGS. 1, 5-7, 9, and 10 , an upper surface 140 of thefirst jointed arm 40 may be defined by the links 110, 120, 130. Theupper surface 140 should allow for engagement of the first jointed arm40 with one of the adjacent vertebral bodies. In some embodiments, theupper surface 140 may include texturing 150 to aid in gripping theadjacent vertebral bodies. Although not limited to the following, thetexturing 150 can include teeth, ridges, friction-increasing elements,keels, or gripping or purchasing projections.

As best seen in FIGS. 7, 9, and 10 a lower surface 160 of the firstjointed arm 40 may be defined by the links 110, 120, 130. The lowersurface 160 should allow for engagement of the first jointed arm 40 withone of the adjacent vertebral bodies. In some embodiments, the lowersurface 160 may include texturing 170 to aid in gripping the adjacentvertebral bodies. Although not limited to the following, the texturing170 can include teeth, ridges, friction-increasing elements, keels, orgripping or purchasing projections.

The second jointed arm 50 has a proximal end 180 and a distal end 190.The proximal end 180 may be pivotally coupled to the distal connectionmember 70. The distal end 190 may be pivotally coupled to the distalconnection member 70. Any of a variety of different fasteners may beused to pivotally couple the proximal end 180 and the distal end 190 andthe proximal connection member 60 and the distal connection member 70,such as pins 100, for example. In another embodiment (not illustrated),the connection may be a hinged connection. As illustrated, the secondjointed arm 50 may comprise a plurality of links that are pivotallycoupled to one another. In the illustrated embodiment, the secondjointed arm 50 comprises first link 200, second link 210, and third link220. When the spacer 10 is in a collapsed position, the first link 200,second link 210, and third link 220 may be generally axially aligned. Asillustrated, the first link 200, second link 210, and third link 220 maybe connected end to end. The first link 200 and the second link 210 maybe pivotally coupled, and the second link 210 and the third link 220 mayalso be pivotally coupled. Any of a variety of different fasteners maybe used to pivotally couple the links 200, 210, 220, such as pins 100,for example. In another embodiment (not illustrated), the coupling maybe via a hinged connection.

As best seen in FIGS. 1, 2, 6, and 8-10 , an upper surface 230 of thesecond jointed arm 50 may be defined by the links 200, 210, 220. Theupper surface 230 should allow for engagement of the second jointed arm50 with one of the adjacent vertebral bodies. In some embodiments, theupper surface 230 may include texturing 240 to aid in gripping theadjacent vertebral bodies. Although not limited to the following, thetexturing 240 can include teeth, ridges, friction-increasing elements,keels, or gripping or purchasing projections.

As best seen in FIGS. 8-10 , a lower surface 250 of the second jointedarm 50 may be defined by the links 200, 210, and 220. The lower surface250 should allow for engagement of the second jointed arm 50 with one ofthe adjacent vertebral bodies. In some embodiments, the lower surface250 may include texturing 260 to aid in gripping the adjacent vertebralbodies. Although not limited to the following, the texturing 260 caninclude teeth, ridges, friction-increasing elements, keels, or grippingor purchasing projections.

With reference now to FIGS. 3, 5, and 9 , a bore 270 extends throughproximal connection end 60. The bore 270 may extend generally parallelto the longitudinal axis 12 (see FIG. 1 ) of the spacer 10. The firstjointed arm 40 and the second jointed arm 50 may define a hollowinterior portion (not shown) that extends axially through the spacer 10.The bore 270 in the proximal connection end 60 may communicate with thishollow interior portion. As best shown on FIG. 5 , the distal connectionend 70 may include an opening 280. As illustrated, the opening 280 mayface inward and may not extend all the way through the distal connection70. In one embodiment, the opening 280 may be generally aligned with thebore 270 in the proximal connection end 60 such at a tool (e.g., tool340 shown on FIG. 12 ) inserted into the bore 270 may be received in theopening 280 for placement of the spacer 10 into a disc space and/orexpansion of the spacer 10.

FIGS. 1-4 illustrate the expandable interbody spacer 10 in a collapsedposition. In accordance with present embodiments, the expandableinterbody spacer 10 may be laterally expanded to an expanded position.FIGS. 6-10 illustrate the expandable interbody spacer 10 in an expandedposition. In the expanded position, the first arm 40 and the second arm50 have each been folded inward in opposite directions. For example, theproximal end 80 and the distal end 90 of the first arm 40 may be foldedcloser together. The links 110, 120, 130 should pivot with respect toone another when the first arm 40 is folded inward. The proximal end 80should pivot at the proximal connection end 60, and the distal end 90should pivot at the distal connection end 70. By way of further example,the proximal end 180 and the distal end 190 of the second arm 50 mayalso be folded together. The links 200, 210, 220 should pivot withrespect to another when the second arm is folded inward. The proximalend 180 should pivot at proximal connection end 60, and the distal end190 should pivot at the distal connection end 70. After placement in theexpanded position, the expandable interbody spacer 10 can be secured inthe expanded position to prevent collapse of the expandable interbodyspacer 10 upon application of spacer. Any of a variety of differenttechniques may be used to secure the expandable interbody spacer 10,including pins or other suitable locking mechanism, for example.

As illustrated by FIG. 6 , the first and second jointed arms 40, 50define an interior cavity 290 when in an expanded position. The interiorcavity 290 may be filled with a bone-growth-inducing material, such asbone material, bone-growth factors, or bone morphogenic proteins. Aswill be appreciated by those of ordinary skill in the art, thebone-growth-inducing material should induce the growth of bone material,thus promoting fusion of the adjacent vertebra.

The expandable interbody spacer 10 may be sized to accommodate differentapplications, different procedures, implantation into different regionsof the spine, or size of disc space. For example, the expandableinterbody spacer 10 may have a width W1 (as shown on FIG. 1 ) prior toexpansion of about 8 to about 22 and alternatively from about 10 toabout 13. By way of further example, the expandable interbody spacer 10may be expanded to a width W2 (as shown on FIG. 6 ) in a range of about26 to about 42 and alternatively from about 16 to about 32. It should beunderstood that the width W1 or W2 whether prior to, or after, expansiongenerally refers to the width of the expandable interbody spacer 10extending transverse to the longitudinal axis 12 of the spacer 10. Ingeneral, the width W2 of the expandable interbody spacer 10 afterexpansion should be greater than the width W1 of the expandableinterbody spacer 10 prior to expansion.

In accordance with present embodiments, the expandable interbody spacer10 may be used in the treatment of damage or disease of the vertebralcolumn. In one embodiment, the expandable interbody spacer 10 may beinserted into a disc space between adjacent vertebrae in which theintervertebral disc has been partially or completely removed. FIG. 11illustrates a spinal segment 300 into which the expandable interbodyspacer 10 (e.g., FIGS. 1-10 ) may be inserted. The spinal segment 300includes adjacent vertebrae, identified by reference numbers 310 and320. Each of the adjacent vertebrae 310, 320 has a correspondingendplate 315, 325. The disc space 330 is the space between the adjacentvertebrae 310, 320. FIG. 12 illustrates a tool 340 that may be used inthe insertion of the expandable interbody spacer 10 into the disc space330. The tool 340 includes a shaft 350 having an elongated end portion360 for coupling to the expandable interbody spacer 10. The elongatedend portion 360 has a distal tip 370.

FIGS. 13 and 14 illustrate introduction of an expandable interbodyspacer 10 into the disc space 330 using tool 340. For illustrativepurposes, the upper vertebra 330 shown on FIG. 11 has been removed fromFIGS. 13 and 14 . As illustrated, the spacer 10 may be secured to thetool 340. For example, the elongated end portion 360 of the tool 340 maybe disposed through the bore 270 (e.g., see FIG. 5 ) in the proximalconnection end 60 with the distal tip 370 (e.g., see FIG. 12 ) of theend portion 360 secured in the opening 280 (e.g., see FIG. 5 ) in thedistal connection end 70. As illustrated by FIG. 13 , the tool 340 mayintroduce the spacer 10 into the disc space 330 through an accesscannula 380. After introduction into the disc space 330, the spacer 10may be laterally expanded. In accordance with present embodiments, thespacer 10 can be laterally expanded by folding the first arm 40 and thesecond arm 50 inward. By expanding laterally, the spacer 10 has anincreased surface area contact with the endplate 325. In addition, thespacer 10 may engage harder bone around the apophyseal ring. Aspreviously mentioned, an interior cavity 290 should be formed in thespacer 10 when in the expanded position. The tool 340 may then bedetached from the spacer 10 and removed from the cannula 380. Asillustrated by FIG. 15 , a funnel 390 may then be placed on the cannula380. Bone-growth inducing material may then be placed into the interiorcavity 290 through the cannula 380. Because the spacer 10 has beenlaterally expanded, the interior cavity 290 should have a desirableamount of space for packing of the bone-growth-inducing material.

FIG. 16 illustrates an expandable interbody spacer 10 in accordance withan alternative embodiment. In the illustrated embodiment, the expandableinterbody spacer 10 comprises a first jointed arm 40 and a secondjointed arm 50. The first jointed arm 40 has a proximal end 80 and adistal end 90. The first jointed arm 40 comprises a plurality of links110, 120, 130 connected end to end, for example, by pins 100. The firstjointed arm 40 further may comprise washers 105 (e.g., PEEK washers)that may be disposed between the links 110, 120, 130 at theirconnections. The second jointed arm 50 has a proximal end 180 and adistal end 190. The second jointed arm 50 comprises a plurality of links200, 210, 220 connected end to end, for example, by pins 100. The secondjointed arm 50 further may comprise washers 105 (e.g., PEEK washers)that may be disposed between the links 200, 210, 220 at theirconnections. Washers 105 may also be disposed between the first arm 40and the proximal connection member 60 and the distal connection member70 at their respective connections. Washers 105 may also be disposedbetween the second arm 50 and the proximal connection member 60 and thedistal connection member 70 at their respective connections. The washers105 should have an interference fit to cause friction such that thespacer 10 may hold its shape in the entire range of the expandedimplant.

The proximal ends 80, 180 may be pivotally coupled, for example, by pin100, as shown on FIG. 19 . The distal ends 90, 180 may also be pivotallycoupled, for example, by pin 100, as shown on FIG. 19 . The firstjointed arm 40 comprises first link 110 and third link 130, the firstlink 110 and the third link 130 being pivotally coupled. In contrast tothe first jointed arm 40 of FIGS. 1-10 , there is no second link 120.

Referring now to FIGS. 17-19 , an expandable interbody spacer 10 isillustrated in accordance with another embodiment of the presentinvention. In the illustrated embodiment, the expandable interbodyspacer 10 comprises a first jointed arm 40 and a second jointed arm 50.The first jointed arm 40 has a proximal end 80 and a distal end 90. Thesecond jointed arm 50 has a proximal end 180 and a distal end 190. Theproximal ends 80, 180 may be pivotally coupled, for example, by pin 100,as shown on FIG. 19 . The distal ends 90, 180 may also be pivotallycoupled, for example, by pin 100, as shown on FIG. 19 . The first jointed arm 40 comprises first link 110 and third link 130, the firstlink 110 and the third link 130 being pivotally coupled. In contrast tothe first jointed arm 40 of FIGS. 1-10 , there is no second link 120. Asshown by FIG. 20 , the third link 130 may comprise a first link segment400 and a second link segment 410, which may be secured to one anotherby pins 420, for example. First link segment 400 and second link segment410 may also have a tongue-and-groove connection, for example a groove430 in the first link segment 400 may receive a tongue 440 of the secondlink segment 410. The second jointed arm comprises first link 200 andthird link 220, the first link 200 and the third link 220 beingpivotally coupled. In contrast to the second joint arm 50 of FIGS. 1-10, there is no second link 210.

In accordance with present embodiments, lateral expansion of theexpandable interbody spacer 10 of FIGS. 17-19 may include folding thefirst arm 40 and the second arm 50 inward. For example, the proximal end80 and the distal end 90 of the first arm 40 may be folded together, andthe proximal end 180 and the distal end 190 of the second arm 50 mayalso be folded together.

Referring now to FIGS. 21 and 22 , an expandable interbody spacer 10 isillustrated in accordance with another embodiment of the presentinvention. In the illustrated embodiment, the expandable interbodyspacer 10 has a proximal end 20 and a distal end 30. The expandableinterbody spacer 10 may include a first jointed arm 40 and a secondjointed arm 50 positioned on either side of longitudinal axis 12 of thespacer 10. As illustrated, the expandable interbody spacer 10 furthermay comprise an internal screw 450. The internal screw 450 may comprisea head 460 and an elongated body 470, which may extend generallyparallel to the longitudinal axis 12 of the spacer 10. In someembodiments, the internal screw 450 may extend from the proximal end 20to the distal end 30 of the spacer 10. In one embodiment, the elongatedbody 470 may be retractable. For example, the elongated body 470 mayretract into the head 460, as shown on FIG. 22 .

As illustrated by FIGS. 23 and 24 , the spacer 10 may be introduced intothe disc space 330, wherein the spacer 10 can be laterally expanded. Inaccordance with present embodiments, the spacer 10 can be laterallyexpanded by folding the first arm 40 and the second arm 50 inward. Insome embodiments, the elongated body 470 may be retracted into the head460 to cause folding of the first arm 40 and the second arm 50 inward,as the first arm 40 and the second arm 50 are secured to the distal end480 of the internal screw 450.

FIG. 25 shows attachment of a tool 490 to the expandable interbodyspacer 10 of FIGS. 22 and 23 in accordance with embodiments of thepresent invention. As illustrated, the tool 490 may have an attachmentend 500, which can be secured to the head 460 of the internal screw 450.As shown by FIG. 26 , the tool 40 can be used to introduce the spacer 10into the disc space 330, wherein the spacer 10 can be laterallyexpanded.

Additional embodiments of expandable interbody spacers are describedherein. FIGS. 27A and 27B show top views of an expandable interbodyspacer having an expandable containment bladder in accordance withembodiments of the present invention. FIG. 27A illustrates the spacer610 in an unexpanded state, while FIG. 27B illustrates the spacer 610 inan expanded state.

As shown in FIG. 27A, the spacer 610 comprises an outer body 615 and aninner bladder 618. The inner bladder 618 can include an opening 620through which an instrument can be inserted to deliver rods or beadsthat will result in expansion of the spacer 610. In some embodiments,the spacer 610 comprises a convex longitudinal surface opposite aconcave longitudinal surface. The spacer 610 can be expanded such thatit maintains the convex longitudinal surface and concave longitudinalsurface, as shown in FIG. 27B. In other embodiments, expansion of thespacer 610 via rods or beads can result in a configuration that isdifferent from the original shape. Advantageously, the spacer 610 isconfigured such that a surgeon can deliver rods or beads to therebytransform the spacer 610 into a desired shape to assist in implantationfrom a variety of different approaches. For example, the spacer 610 canbe expanded such that it includes a “banana” type shape that is suitablefor transforaminal delivery, or it can be a long, slender shape that issuitable for posterior delivery. In its unexpanded state, the spacer 610can be easily delivered minimally invasively into a desired anatomicallocation.

As shown in FIG. 27B, the spacer 610 can receive an instrument 690through the opening 620 in the inner bladder 618. The instrument 690 candeliver one or more rods or beads 688 that will cause expansion of theinner bladder 618, as well as the overall spacer 610. In someembodiments, the instrument 690 can be a curvable instrument that candeliver the beads 688 to desirable locations within the inner bladder618, thereby causing selective expansion of the spacer 610. As shown inFIG. 27B, in some embodiments, the spacer 610 can substantially maintainthe same shape as in the unexpanded state; however, with the addition ofthe rods or beads 688, the spacer 610 will be larger and have a muchlarger footprint than in the unexpanded state. In some embodiments, theoverall footprint of the spacer 610 expands along its longitudinallength and/or width, while maintaining a substantially or the sameheight as the unexpanded spacer 610. In other embodiments, the overallfootprint of the spacer 610 expands along its longitudinal length and/orwidth, and the height of the spacer 610 also changes during expansion.

FIG. 27C illustrates a third view of the spacer 610 with the expandableinner bladder 618 inserted between two adjacent vertebrae 310, 320. Thespacer 610 is configured to receive one or more rods or beads 688 viathe delivery instrument 690. As shown from this view, the deliveryinstrument 690 can comprise a tubular body that holds the rods or beads688 in serial formation. The delivery instrument 690 can be accompaniedby a pusher instrument 685 that can deliver the rods or beads 688 out inseries. In some embodiments, the delivery instrument 690 can alsoinclude an automatic depositor such that multiple rods or beads 688 canbe delivered in rapid fashion.

FIGS. 28A and 28B show top views of an expandable spacer utilizing ashim member in accordance with embodiments of the present invention. Theexpandable spacer 710 comprises an outer body 715 having an opening 718,as shown in FIG. 28A. In some embodiments, the opening 718 is incommunication with a channel 723 having opposing walls 724, 725 thatextends along a longitudinal axis of the expandable spacer 710. In someembodiments, the channel 723 extends along at least a majority of thelength of the expandable spacer. When it is desired to expand the spacer710, a shim member 720 can be inserted through the opening 718 and intothe channel 723, as shown in FIG. 28B. The addition of the shim member720 causes the spacer 710 to expand by a distance as measured by theincrease in distance between the opposing walls 724, 725 of the channel,thereby advantageously increasing the footprint of the spacer 710 onceimplanted in a desired location. In some embodiments, the shim member720 is tapered such that the tapering facilitates ease of insertion inthe channel 723.

FIGS. 29A and 29B show top perspective views of an expandable spacerutilizing a translation member in accordance with embodiments of thepresent invention. FIG. 29A illustrates the spacer 810 in a closedconfiguration, while FIG. 29B illustrates the spacer 810 in an open orexpanded configuration.

The expandable spacer 810 comprises an upper endplate 812 and a lowerendplate 814. Each of the upper endplate 812 and the lower endplate 814can include surface texturing 815 thereon to assist in engagement withan adjacent vertebra. In some embodiments, the surface texturing 815comprises protrusions, teeth, ridges or ribbing. Each of the endplates812, 814 is formed of two separate members that can be separated fromone another laterally in a “v” configuration, as shown in FIG. 29B. Withreference to the upper endplate 812, the upper endplate 812 includes afirst endplate portion 822 and a second endplate portion 824 that can beseparated from one another along a midline 805 that extends through thespacer 810. In some embodiments, at least one of the first endplateportion 822 and the second endplate portion 824 can be connected via ahinge member 855 such that at least one of the endplate portions pivotsaway from one another. As shown in FIG. 29B, the first endplate portion822 and the second endplate portion 824 of the upper endplate 812transition into corresponding members found along the lower endplate814. In some embodiments, the expandable spacer 810 comprises one ormore side slots 828 that can be engaged by an installation instrument toassist in delivery of the spacer 810 to a desired anatomical location.

In order to expand the spacer 810, the spacer 810 includes a translationmember 830 and an actuation member 840, as shown in FIG. 29B. Thetranslation member 830 can comprise one or more ramps that engage sideramps formed along inner sidewalls of the spacer 810. As shown in FIG.29B, the spacer 810 can include at least a pair of ramps 832, 834 thatengage with corresponding ramps formed along the inner sidewalls of thespacer 810. As the translation member 830 is translated (e.g., in afirst direction), the ramps 832, 834 slide along corresponding rampsformed along the inner sidewalls of the spacer 810, thereby causingexpansion of the implant. Translation of the translation member 830 inan opposite direction (e.g., in a second direction) causes contractionof the implant. In some embodiments, the spacer 810 includes more thanjust the ramps 832, 834. For example, the ramps 832, 834 can beconnected via a bridge member 836 to additional ramps along alongitudinal axis of the spacer 810. In some embodiments, ramps 832, 834are connected via a bridge member 836 to a second pair of ramps that canhelp with expansion of the spacer 810.

In order to move the translation member 830, in some embodiments, thetranslation member 830 is operably attached to an actuation member 840.The actuation member 840 can comprise an actuation or set screw 840. Insome embodiments, the actuation member 840 includes an opening, such asa hex screw opening, for allowing rotation of the actuation member 840.Rotation of the actuation member 840 in a first direction causes lateraltranslation of the translation member 830 in the first direction,thereby causing sliding engagement between the ramps 832, 834 of thetranslation member 830 and ramps of the inner sidewalls, and thusoutward expansion of the first endplate portion and second endplateportion. Advantageously, as shown in FIG. 29B, the first endplateportion 822 separates from the second endplate portion 824 in a v-shape,thereby enlarging the footprint of the implant. This advantageouslycreates an implant with greater load stability, as well as an increasedregion through which to deposit bone graft material.

FIGS. 30A and 30B show top views of an expandable spacer including asliding actuation member in accordance with some embodiments. Theexpandable spacer 910 includes a pair of upper wing members 912 and apair of lower wing members 914. As shown in FIG. 30A, an upper wingmember 912 and a lower wing member 914 is operably attached to slidingactuation member 920. FIG. 30A illustrates the expandable spacer in anunexpanded configuration. When the spacer is ready for expansion, thesliding actuation member 920 can slide in between the upper wing member912 and the lower wing member 914, thereby causing the wing members toopen outwardly, as shown in FIG. 30B. In some embodiments, the wingmembers can expand from approximately 12 mm to 20 or more millimetersjust by expansion of the wing members.

FIGS. 31A and 31B show an alternative embodiment of an expandable spacerhaving slidable wings in accordance with embodiments of the presentinvention. The spacer 1010 can be composed of slidable wings 1012, 1013,1014, 1015. As shown in FIG. 31A, slidable wings 1012, 1013 are on aleft side of the spacer 1010, while slidable wings 1014, 1015 are on aright side of the spacer 1010. The spacer 1010 can be delivered to adisc space in a non-expanded, minimally invasive state, as shown in FIG.31A. Once in the disc space, the wings 1012, 1013, 1014, 1015 of theexpandable spacer can be outwardly deployed, thereby causing expansionof the device. In some embodiments, the wings can be complimentary andsymmetrical to one another prior to deployment. To deploy the wings, apre-attached block member 1022, 1023 can be actuated to open the wings.As shown in FIG. 31A, block member 1022 can operate wings 1012, 1013,while block member 1023 can operate wings 1014, 1015. FIG. 31B shows thewings separated and in an expanded state following actuation by theblock members.

FIGS. 32A-32D show an expandable spacer comprising an “I-beam” withmultiple side slots for receiving complementary side members inaccordance with embodiments of the present invention. The spacer 1110can comprise a central I-beam 1111 with one or more side slots 1116 thatreceive protruding portions from adjacent side members 1112, 1114. Asshown in FIG. 32A, the I-beam and its side members 1112, 1114 complementeach other. The I-beam can include a slot 1118 for receiving anactuation member to outwardly expand the side members 1112, 1114. Insome embodiments, in a contracted configuration, the side slots 1116 ofthe I-beam receive the protruding portions 1119 of the adjacent sidemembers 1112, 1114. Upon expansion, the protruding portions 1119 of theadjacent side members will be offset with the side slots 1116 of theI-beam. To offset the protruding portions 1119 of the adjacent sidemembers from the side slots 1116, the I-beam can be slid in a firstdirection such that the protruding portions move away from the slots. Insome embodiments, the protruding portions 1119 can be tapered to allowsliding between the I-beam and the protruding portions. In otherembodiments, the actuation member can be any of the actuation componentsdiscussed herein for expanding and/or contracting the spacers.

FIGS. 33A and 33B show different views of a hinged expandable interbodyspacer in accordance with embodiments of the present invention. FIG. 33Aillustrates the spacer 1210 in an unexpanded state and FIG. 33Billustrates the spacer 1210 in an expanded state within a vertebralspace 3. As shown in FIG. 33A, the spacer 1210 can comprises twoexpandable portions 1212, 1214 that are connected to each either by ahinge joint 1210. In the unexpanded state, the two expandable portions1212, 1214 of the spacer 1210 can be positioned side-by-side or adjacentto one another. In some embodiments, inner facing side surfaces of thetwo expandable portions 1212, 1214 are in direct contact with oneanother in the unexpanded state.

To expand the spacer 1210, a wedge member 1219 can be delivered inbetween the two expandable portions 1212, 1214. The wedge member 1219can be inserted where the inner side surfaces of the expandable portions1212, 1214 meet, thereby separating the first expandable portion 1212from the second expandable portion 1214. As the first expandable portion1212 and the second expandable portion 1214 are connected via a hinge1215, the spacer 1210 will assume an expanded v-shape upon expansion, asshown in FIG. 33B. In some embodiments, the wedge member 1219 cancomprise a triangular wedge member. As shown in FIG. 33B, the wedgemember 1219 can be placed substantially adjacent to or in contact withthe hinge 1215 in some embodiments. In some embodiments, in the expandedconfiguration, the wedge member 1219 can advantageously remain embeddedwithin the v-shape of the expanded spacer 1210, thereby preventingclosing or contraction of the expanded configuration.

In some embodiments, the wedge member 1219 can be accompanied by aninsertion instrument 1223 to assist in delivery of the wedge member1219. The wedge member 1219 can comprise a proximal end and a distal endthat is directly adjacent and/or in contact with the expandable portions1212, 1214. The insertion instrument 1223 includes a sleeve to guide thewedge member 1219 to a desired location between the hinged expandableportions 1212, 1214.

FIGS. 34A-34D show different embodiments of an alternative hinged spacer1310 in accordance with some embodiments. FIG. 34A illustrates a hingedspacer 1310 in an unexpanded configuration, while FIG. 34B illustratesthe hinged spacer 1310 in an expanded configuration. The hinged spacer1310 comprises a first expandable portion 1312, a second expandableportion 1313, and a third expandable portion 1314 that are connected toone another via hinges 1315, 1316.

In order to expand the hinged spacer 1310, the spacer 1310advantageously provides a holding point 1322 and a pushing point 1324(as shown in FIG. 34C). The holding point 1322 is a point at which aninsertion instrument can steadily hold the spacer 1310. In someembodiments, an insertion instrument will hold the spacer 1310 bygripping a surface. In other embodiments, an insertion instrument canengage the spacer 1310 via one or more insertion surfaces (e.g., athreaded hole) that are formed in the holding point 1322. While thespacer 1310 is being held at its holding point 1322, the insertioninstrument can further comprise a pusher that expands the spacer 1310 byapplying a force on the surface of the pushing point 1324. In someembodiments, a pushing instrument that is separate from the insertioninstrument can be used (e.g., inserted through the insertion instrument)such that it causes expansion of the spacer 1310. As shown in FIGS. 34Cand 34D, the expandable spacer 1310 can advantageously be expanded insitu.

FIGS. 35A and 35B show an expandable spacer including a flexiblecontainment member in accordance with some embodiments. FIG. 35Aillustrates the spacer 1410 in an unexpanded state, while FIG. 35Billustrates the spacer 1410 in an expanded state within a disc space 3.The expandable spacer 1410 can comprise a flexible containment structure1411 that includes one or more channels 1413 for receiving blocks 1422.Insertion of the blocks 1422 causes the channels to fill, therebycausing expansion of the spacer 1410. Advantageously, the flexiblecontainment structure 1411 can be inserted into a disc space with few ifany blocks such that the spacer 1410 can be inserted through as small anincision as possible. After the spacer 1410 is placed in a desiredposition in a disc space, blocks 1422 can be added into the flexiblecontainment structure 1411 to fill the channels, thereby causingexpansion of the spacer 1410 in situ.

The flexible containment structure 1411 of the spacer 1410 can comprisesone or more channels to accommodate the blocks. As shown in FIG. 35B,the flexible containment structure 1411 can include a number of channels1412, 1414, 1416, 1418. In some embodiments, the channels are of a samesize and shape, while in other embodiments, the channels can be of adifferent size and shape in order to more closely approximate thedesired anatomical shape of the disc space. In some embodiments, theflexible containment structure 1411 can be comprised of a flexiblematerial, such as a plastic, a rubber, or other elastomeric material. Insome embodiments, the flexible containment structure 1411 can comprise awoven or braided member that expands with the addition of the blocks.

To assume their expanded configuration, the channels 1412, 1414, 1416,1418 of the flexible containment structure 1411 are configured toreceive one or blocks 1422 in each of the channels in order to for themto reach their maximum size. In some embodiments, the channels can eachreceive the same number of blocks, while in other embodiments (as shownin FIG. 35B), the channels can receive different numbers of blocks.Advantageously, by providing channels that accommodate a differentnumber of blocks, a specific anatomical footprint can be achieved withinthe disc space that caters to different patients of different sizes. Insome embodiments, the blocks 1422 can be formed of a polymeric material,such as PEEK.

In some embodiments, an instrument is capable of directing the blocks1422 to individual channels in order to cause selective expansion of theimplant 1410. In other embodiments, the blocks 1422 fill the channelsthemselves without any specific directing by an instrument. The channelscan be made of a distinct size such that upon filling, the blocks 1422will fill other regions of the implant 1410, without having to bedirected by an insertion instrument.

FIG. 36 shows an expandable spacer 1510 including a rotating cam toactuate expandable wings in accordance with some embodiments. Rotationof the cam 1520 in a first direction causes wings 1522, 1524 tooutwardly expand, wherein rotation of the cam 1520 in a second directionopposite the first causes wings 1522, 1524 to inwardly contract.

FIGS. 37A and 37B show an expandable spacer including four wingsactuated by a gear mechanism in accordance with some embodiments. Thespacer 1610 comprises four wings 1622, 1624, 1626, 1628 that can be keptin a contracted state (FIG. 37A) and then expanded into an expandedstate (FIG. 37B) using a gear mechanism 1630. Advantageously, the gearmechanism, which can include levers, pivoting arms, etc., can controlthe expansion of the wings such that the wings need not be fullyexpanded. In other words, the expandable spacer 1610 can have a seriesof increased expansion widths, rather than just a single contractedstate and a single expanded state.

FIGS. 38A and 38B show an expandable spacer 1710 comprising deployablepins in accordance with some embodiments. In contrast to prior spacersthat expand to provide a greater footprint in a disc space, the presentspacer 1710 (via its pins 1722) expands in a superior and/or inferiordirection in order to conform superior and inferior endplates 1712, 1714of the spacer 1710 with adjacent vertebrae.

FIG. 38A illustrates the spacer 1710 in an unexpanded state. The spacer1710 comprises a superior endplate 1712 and an inferior endplate 1714having a plurality of holes or openings 1721 therethrough. Within theopenings 1721 are a plurality of deployable pins 1722 that can outwardlyexpand through the openings 1721 in order to increase the height of thespacer within the disc space. In some embodiments, the spacer 1710 bodycan comprise a port 1715 for receiving an expandable member 1718 (shownin FIG. 38B) that can outwardly deploy the pins to increase the heightof the spacer 1710.

FIG. 38B illustrates the spacer 1710 in an expanded state. From thisview, one can see an expandable member 1718 within the body of thespacer 1710. Expansion of the expandable member 1718 within the body ofthe spacer 1710 causes the deployable pins 1722 to expand outwardly,thereby increasing the height of the spacer 1710. In some embodiments,the expandable member 1718 can comprise a balloon member. In someembodiments, an expansion instrument is insertable through the port1715. The expansion instrument is capable of inflating or enlarging theexpandable member 1718. As the expandable member 1718 expands, exteriorsurfaces of the expandable member 1718 push against the deployable pins1722, thereby causing the pins 1722 to protrude outwardly and causeoverall height expansion of the spacer 1710.

FIG. 39 shows an expandable spacer expandable via a guide wire inaccordance with some embodiments. The spacer 1810 comprises two or morelinked members that can be fed into a disc space via a guide wire.Advantageously, the spacer 1810 can be inserted into a small incisionthat is about the width of a single linked member. The linked memberscan be attached to a guide wire or k-wire 1826 that extends through eachof the linked members. As the spacer 1810 is fed into the disc space,the natural anatomy of the disc space causes the linked members to curveand expand to widen the footprint of the device. As shown in FIG. 39 ,the spacer 1810 can comprise at five linked members 1812, 1814, 1816,1818, 1820. In other embodiments, the spacer 1810 comprises less thanfive linked members or greater than five linked members. The linkedmembers can be connected to adjacent members via a joint 1824 (such as ahinge joint). Each of the linked members can include an opening forreceiving the k-wire 1826. Following expansion of the implant in situ,the k-wire 1826 can be removed, thereby leaving the implant in place.The k-wire 1826 can be delivered by an instrument 1830.

FIG. 40 shows an expandable spacer including an add-on member inaccordance with some embodiments. This spacer 1910 includes a firstmember 1912 and a second member 1914 that can be inserted into a discspace 3 on their own. As shown in FIG. 40 , the first member 1912 andthe second member 1914 can be elongated members in the form of rods thatare joined together at a hinge or joint 1922. The first member 1912 andthe second member 1914 can be inserted in a configuration whereby thetwo members are in contact with each other. Once the first member 1912and the second member 1914 are inserted into the disc space 3, the twomembers can be expanded into a V-shape configuration, such that they areready to receive a third add-on member 1916.

The third add-on member 1916 can be inserted into the disc space 3 andcan be attached to the first member 1912 and second member 1914 atrespective joints or hinges 1924, 1926. In some embodiments, the thirdadd-on member 1916 can be snap-fitted to the first two members. In otherembodiments, the first member 1912 and the second member 1914 includeopenings near the joints 1924, 1926 for receiving the third add-onmember 1916 easily therethrough. With the third add-on member 1916, theimplant can assume the shape of a triangle that advantageously has alarge footprint within the disc space 3. Bone graft material can beprovided into the completed spacer 1910, thereby helping to aid in afusion process within the disc space.

FIG. 41 shows a buildable spacer 2010 that can be guided by tracks in adisc space to form a large footprint in a disc space in accordance withsome embodiments. In this embodiment, multiple tracks 2022, 2024, 2026can be formed within a disc space 3 to guide individual spacer members2012, 2014 into desired positions within the disc space. The tracks2022, 2024, 2026 can be pre-laid within a disc space prior to insertingthe spacer members 2012, 2014. In some embodiments, the tracks 2022,2024, 2026 can compose tracks formed by the disc space itself (e.g., asurgeon can form the tracks out of the cut bone), while in otherembodiments, the tracks 2022, 2024, 2026 can be formed by insertedmaterials within the disc space, such as metals, polymers or bonematerial. Once the tracks 2022, 2024, 2026 have been laid, individualspacer members 2012, 2014 in the form of elongated members or rods canbe inserted and guided by the individual tracks, thereby creating aspacer with an expanded footprint in situ. Advantageously, in someembodiments, the spacer members 2012, 2014 can be inserted individuallyinto the disc space, thereby requiring a small incision. As the spacermembers 2012, 2014 are guided in the track, the spacer 2010 size isincreased. In some embodiments, there are more tracks than spacermembers, thereby advantageously providing multiple options forconfiguring the implant in situ.

FIGS. 42A-D show a rotatable spacer capable of expansion followingrotation in accordance with some embodiments. The spacer 2110 comprisesa pair of expandable panels 2130, 2132 that are capable of expansionfollowing rotation of the spacer 2110 in a disc space. The spacer 2110includes a leading edge 2112, a trailing edge 2114, a bottom surface2121 and a top surface 2123. The spacer 2110 can be inserted in a firstdirection in a minimally invasive manner via its leading edge 2112. Oncewithin the disc space, the spacer 2110 can be rotated, such as 90degrees. After rotation, the panels 2130, 2132 of the spacer 2110 can beadvantageously expanded, thereby exposing a graft slot 2135 therein. Insome embodiments, the footprint of the spacer 2110 can increase by atleast 20-30 percent. For example, in some embodiments, the width of thespacer 2110 can expand from an initial 20 mm width to at least a 30 mmwidth, with a desirable volume in the middle of the spacer 2110 forreceiving graft material.

FIGS. 43A-C show an expandable spacer capable of outward folding inaccordance with some embodiments. The spacer 2210 comprises a firstsection 2212 and a second section 2214 that are operably connected via ajoint or hinge 2218. As shown in FIG. 43A, the spacer 2210 can have aminimally invasive configuration whereby the first section 2212 and thesecond section 2214 are inwardly folded together.

Once the spacer 2210 is inserted into a disc space, the spacer 2210 canbe expanded whereby its first section 2212 and second section 2214 areoutwardly folded. As shown in FIG. 43B, the spacer 2210 in its expandedstate can reveal surface protrusions or teeth 2220 along at leastportion of the first and second sections 2212, 2214. In someembodiments, the surface protrusions 2220 extend along a majority of theperimeter of each of the first and second sections 2212, 2214. Thesesurface protrusions 2220 advantageously provide a gripping surface toprevent extrusion of the spacer 2210 once it has been expanded within adisc space.

FIG. 43C illustrates an alternative embodiment of the spacer 2210. Insome embodiments, the expanded spacer 2210 can reveal multiple embeddedlayers. The spacer 2210 can have first and second outer sections 2212 a,2214 a, first and second mid sections 2212 b, 2214 b and first andsecond inner sections 2212 c, 2214 c. Each of these sections can includesurface protrusions or teeth. With the multiple embedded layers, thespacer 2210 advantageously provides greater surface area for engagementwith adjacent vertebrae and also a greater covered footprint for betterloading distribution.

FIGS. 44A and 44B show a pair of expandable spacers having deployablearms. The spacers 2310 comprise an elongated body 2312 having one ormore arms 2314 extending from the body 2312. In some embodiments, thearms 2314 are flexible members that can be bent along the length of thebody 2312 prior to deployment, thereby providing for minimally invasiveinsertion. In other embodiments, the arms 2314 are more rigid membersthat can be deployed via an instrument that can be inserted through thebody 2312 of the spacer 2310. For example, when the arms 2314 are readyfor deployment, an instrument can be inserted along the length of thebody 2312 to release or outwardly rotate the deployable arms 2314. Inother embodiments, the arms 2314 can be inflatable, such as by adding anexpandable medium into the arms.

FIG. 44A shows the spacer 2310 in an unexpanded configuration, whileFIG. 44B shows the spacer 2310 in an expanded configuration with thearms 2314 deployed. With the arms outwardly deployed, the spacer 2310advantageously has a larger footprint in a disc space compared to whenit is first inserted into the disc space. In addition, in someembodiments, one or more arms 2314 can include one or more ports 2320.Advantageously, these ports 2320 can serve as graft windows, such thatgraft material can be delivered therein. While the illustratedembodiment shows the arms 2314 as having a single port in each arm, inother embodiments, two or more ports can reside on the arms. Moreover,in some embodiments, the elongated body 2312 can also include ports orgraft windows for receiving bone graft material therein.

FIGS. 45A-45C show an expandable spacer having a rack and pinionactuator in accordance with some embodiments. The spacer 2510 comprisestwo or more linking members 2512 that are joined together at joints orhinges. In some embodiments, the spacer 2510 can include a rack andpinion actuator that allows the spacer to be pulled in the direction2518. The rack and pinion actuator advantageously allows the spacer toexpand incrementally, thereby allowing a surgeon to control the shape ofthe spacer within different types of patients. In some embodiments, therack and pinion spacer will be controlled to sit on an apophyseal ringof the patient, thereby providing desirable load distribution when inuse. In some embodiments, the spacer 2510 can include a graft window2517 that can receive graft material therein.

FIGS. 46A-46C show an expandable spacer having an outer member with aslidable inner member therein. The spacer 2610 comprises an outer member2612 including an inner member 2614 capable of sliding in and out of theouter member 2612. As shown in FIG. 47A, the spacer 2610 can have afirst, unexpanded configuration whereby the inner member 2614 issubstantially within the body of the outer member 2612. After beinginserted into a disc space, the inner member 2614 can be slid outwardfrom the outer member 2612, thereby causing expansion of the spacer 2610and a greater footprint.

FIG. 46C shows a side view of the expandable spacer and a mechanism forsliding the inner member 2614 out of the outer member 2612 according tosome embodiments. In some embodiments, in order to slide the innermember 2614 in and out of the outer member 2612, the inner member 2614can include pin members 2624 that ride in slots 2622 formed in the outermember 2612, until a desired expansion of the inner member 2614 isreached. In some embodiments, the pin members 2624 can be locked at anypoint along the length of the slots, such as by rotating the pin members2624. In other embodiments, the pin members 2624 have designatedunlocking/locking points, located at designated parts of the slots 2622.

FIGS. 47A and 47B show an expandable spacer having upper and lowermembers separated by linking members in accordance with someembodiments. The expandable spacer 2710 comprises an upper member 2712and a lower member 2714. FIG. 47A shows the upper member 2712 and thelower member 2714 in a first initial configuration whereby the lowermember 2714 is positioned near or adjacent to the upper member 2712. Toseparate the lower member 2714 from the upper member 2712 and form alarger footprint, the lower member 2714 can be moved away from the uppermember 2712 via linking members 2722 and 2724. In some embodiments, thelinking members 2722, 2724 can be moved by moving respective pins 2732,2734 along slots 2742, 2744 formed in the upper member 2712. In otherembodiments, the lower member 2714 can be moved away from the uppermember 2712 via a gear mechanism, such as a gear drive (e.g., a wormgear).

FIGS. 48A and 48B show an expandable spacer comprising a worm gear inaccordance with some embodiments. The expandable spacer 2810 comprisessix linking members 2812 that can expand via a worm gear 2840. The wormgear 2840 can be engaged by an instrument 2850, such as a worm drive.Rotation of the instrument 2850 causes actuation of the worm gear 2840,thereby causing expansion of the linking members 2812. As shown in FIG.48B, the expandable spacer 2810 can be expanded such that it forms aring member having a larger footprint than its initial configuration. Insome embodiments, the worm gear 2840 can be built into the spacer 2810,while in other embodiments, the worm gear 2840 can be removeablyattached to the spacer 2810.

FIGS. 49A and 49B show an expandable spacer having asymmetricalexpansion in accordance with some embodiments. The spacer 2910 includesfive different linking members 2912, 2913, 2914, 2915 and 2916 that areconnected to one another via a joint or hinge. In some embodiments, thelinking members can be connected to one another via a click fit. FIG.49A shows the spacer 2910 in its initial, non-expanded configuration andattached to an instrument 2930. The instrument 2930 can deliver thespacer 2910 into a disc space, whereby the spacer 2910 can be pulled inthe direction 2922, thereby causing expansion of the spacer 2910, asshown in FIG. 49B. Advantageously, expansion of the spacer 2910 can beasymmetrical to accommodate a desirable footprint within a disc space.

The described embodiments are capable of insertion into a disc space,and subsequent expansion. In some embodiments, the implants will beexpanded into a desirable lordotic form. In some embodiments, theimplants will be expanded such that the footprint is increased. Theimplants can be expanded such that they rest on an apophyseal ring of apatient. While the above descriptions describe numerous embodiments, oneskilled in the art will appreciate that any of the embodiments discussedabove are unique and novel features that may be combinable with oneanother.

While the invention herein disclosed has been described by means ofspecific embodiments and applications thereof, numerous modificationsand variations can be made thereto by those skilled in the art withoutdeparting from the scope of the invention as set forth in the claims.

What is claimed is:
 1. An expandable interbody spacer comprising: afirst jointed arm comprising a first plurality of links coupled end toend; a second jointed arm comprising a second plurality of links coupledend to end; and an elongate screw having a head portion positionedoutside of the first and second jointed arms and an elongate body,wherein the first jointed arm and the second jointed arm areinterconnected at a proximal end of the expandable interbody spacer,wherein the first jointed arm and the second jointed arm areinterconnected at a distal end of the expandable interbody spacer, andwherein the first jointed arm and the second jointed arm are eachconfigured to move in opposite directions to place the expandableinterbody spacer in an expanded position.
 2. The expandable interbodyspacer of claim 1, wherein the expandable interbody spacer furthercomprises a proximal connection member interconnecting the first andsecond jointed arms, wherein a proximal end of each of the first andsecond jointed arms is coupled to the proximal connection member.
 3. Theexpandable interbody spacer of claim 2, wherein the proximal connectionmember comprises a bore that communicates with a hollow interior portionof the expandable interbody spacer defined by the first and secondjointed arms, the hollow interior portion extending axially through theexpandable interbody spacer.
 4. The expandable interbody spacer of claim1, wherein the expandable interbody spacer further comprises a distalconnection member interconnecting the first and second jointed arms,wherein a distal end of each of the first and second jointed arms iscoupled to the distal connection member.
 5. The expandable interbodyspacer of claim 1, wherein the first jointed arm comprises upper andlower surfaces defined by the first plurality of links configured toengage adjacent vertebrae, and wherein the second jointed arm comprisesupper and lower surfaces defined by the second plurality of linksconfigured to engage adjacent vertebrae.
 6. The expandable interbodyspacer of claim 1, wherein the expandable interbody spacer has a widthof about 8 mm to about 22 mm prior to expansion and a width of about 26mm to about 42 mm after expansion.
 7. The expandable interbody spacer ofclaim 1, wherein the first plurality of links comprises three links, andwherein the second plurality of links comprises three links, whereinwashers are disposed between adjacent ones of the links.
 8. Theexpandable interbody spacer of claim 1, wherein one of the firstplurality of links of the first jointed arm comprises a first linksegment coupled to a second link segment, the first link segment and thesecond link segment having a tongue-and-groove connection.
 9. Theexpandable interbody spacer of claim 1, comprising an internal screwextending axially through the expandable interbody spacer from aproximal end to a distal end.
 10. The expandable interbody spacer ofclaim 1, wherein an exterior sidewall of at least one of the secondplurality of links is straight and transitions into a second roundedportion.
 11. An expandable interbody spacer comprising: a first jointedarm comprising a first plurality of links coupled end to end, whereinthe first plurality of links define upper and lower surfaces configuredto engage adjacent vertebrae, wherein an exterior sidewall of at leastone of the first plurality of links is straight and transitions into arounded portion; a second jointed arm comprising a second plurality oflinks coupled end to end, wherein the second plurality of links defineupper and lower surfaces configured to engage adjacent vertebrae,wherein an exterior sidewall of at least one of the second plurality oflinks is straight; and an elongate body extending through a proximalend, into an interior region, and into a distal end of the interbodyspacer, wherein the elongate body is configured to expand the interbodyspacer, wherein the first jointed arm and the second jointed arm areinterconnected at the proximal end and the distal end of the interbodyspacer.
 12. The expandable interbody spacer of claim 11, wherein theinterior region is a hollow interior portion defined by the first andsecond jointed arms.
 13. The expandable interbody spacer of claim 12,wherein the second jointed arm comprises an opening that extends throughthe rounded portion of the spacer.
 14. The expandable interbody spacerof claim 13, wherein the opening faces inward into the spacer and doesnot extend entirely through the second jointed arm.
 15. The expandableinterbody spacer of claim 11, wherein the upper and lower surfaces ofthe first jointed arm comprise texturing to aid in gripping thevertebrae, and wherein the upper and lower surfaces of the secondjointed arm comprise texturing to aid in gripping the vertebrae.